Island



(No Mode1.)

J. W. WHITE. FIRE ALARM SYSTEM. No. 524,973. Patented Aug. 21; 1894.

UNITED STATES PATENT? O IC JOEL WALES WHITE, or PROVIDENCE, RHoDE ISLAND, ASSIGNOR OF ONE-- HALF To ASHBEL T. WALL AND GEORGE'A. WALL.

FIRE-ALARM SYSTEM.

srnomcn'rron forming part of Letters Patent No. 524,973, dated August 2-1, 1894.

' Application filed May 28,1894. Serial No. 512,753. (No model.)

long been known; but owing to the fact that the apparatus is likely to remain unused for long periods of time and tothe further 'fact that itis likely to get out of order before the occasion arises for its operation, its use has been much restricted.

Theobject of the presentinvention is. to provide a system of this kind-whiclr will give notice automatically when it is out of order, whether from accident or design and generally to make the use of' thermostats as automatic fire alarms so certain and eflicient that full confidence can be reposed in such asystem in spite of the fact that no occasion for its oporation 'as a fire alarm may arise for years after it is constructed. r s

The invention consists in the combination of a thermostat having three electrodes, with two circuits one of which is closed andthe other open, the closed circuit-and the open circuit having one electrode of the thermostat in common; and-bothcircuitsbeing provided with suitable translating devices, but

' the closed circuit being through a-loop about all the thermostats, with such a resistance in that loop that the normal current in the closed circuit is small and serves simply to move the needle or pointer of its translating device to an intermediate position indicating that the apparatus is in order; allaswill now. be more fully explained by reference to the diagram The thermostats A will be arranged as 1 usual, and may be of any usual construction, except that each must have three electrodes a a a insteadot but two as in thermostats heretofore used. As anexamplethese thervmostatswill be arranged on the floors of a building andall the thermostats on the several floors may constitute one series so far as,

concerns the closed circuit, its translating de- -vice B and its rheostat R; but those on .one

floor -only will constitute a series so far as concerns'the open circuit and itsannunciato'r, 5 5 or other. translating 'devicelfi'. This'is in orderthat those in charge of the system may have a number of indicators such as B constantly under the care of an attendant, while the annunciators B may be arranged in a: properplace in the building which is to be protected; each indicator thus representing at the central ofiice a given building but each annunciator in any building representing one of the floors of that building. v

The spring a, or other moviug' part of each thermostat -A is in electrical connection with the electrodes which is grounded, asxby the: wire b, or otherwise; and the electrodes a anda, are insulated from the spring ax untilthe 7o temperature about the thermostat rises to the danger point, when the spring a is released by the melting 'of the solder by which thespring a is'held under stress; whereupon the spring a makescontact with the electrodes a 7 5' and a and thereby completes an electrical connection between all :three electrodes, a a

a Of course two thermostats, each with but two electrodes, asnow commonly made, will] answer inplace of a single thermostat with three electrodes, if one, electrode of each of the two' thermostats with but two electrodes be connected with the wire I), or otherwise groundedybut for certainty of operation a single thermostat with three electrodes is 85. preferable to two thermostats each with twov electrodes but made the equivalent of a; sin

gle thermostat with three electrodes by con necti ng two of the electrodes together.

The closed cipcuit in the diagram is from 0 generator G grounded at-E through wire I), galvanometer B, wire bi, through loop I) and rheos'ta't R to electrode a of the thermostats,- and from electrodes a by wire b to ground E; and the open circuitfrom generator G 5 I grounded at E through wire I) annunciator B, wire If, to the electrode a of thermostats connected by-wire b and-when the open circult is closed by electrical connection of wires.

1) or b with wire b, through electrodes a and a 1 00 (or otherwise when testing the apparatus) the I open circuit is completed through wire b to 'ground E' thus operating B'. Of ccurse'me- ,tallic circuits may be used, that i'sa? maybe connected by a wire to the proper pole of G, and'to the proper pole of G'".

- icircuitw'ill be small but suflicient to keep; the 7 index of the galvanometer B at a point. be-

' v tween'two other points, one of which on the Jeft in the diagram indicates that the appara 'ro tus is out of order, as bylhe rupture, or rusting out, of wire'b or failure of generator G, or the like,;-preventing suificient currentin the closed circuit t'okeep the index of B at its proper point to indicate good-order; and the 1 other of which onthe right in the diagram,-

indicates that the thermostats have operated or that there is an excess of current above'the' normal; for when wire I) is connected to wire "b by the operation of any thermostatcausing an electr c connection between aand a the current instantly increases through B; and so if wire, I) he accidentally grounded or if, for any 'In case the temperature atany thermostat 25' becomes excessive-the electrodes a a and-us v i mlble alarm. 5 rm -lly 13116 current through th elose'd,

reason, an excess of current passes through B.

fre'ntis; establishedthrough B and a current is alsoestablished through B, thus givinga While no. broad.c1aini ismad e to any part 30 ofthe'apparatus' the combination of the elemerits necessary to produce a double automatic fire alarm system which automatically 1 gives notice of any derangement unfitting. it

for its intended operation, and which is other- 3 5 wisepractically efficient is new.

What is claimed as the invention is I A fire alarm system comprisinga closed circuit containing" a resistance and translating device, an open circuit containingatranslat- 4o ing device, a'thermostat having three electrodesfa shunt. around the resistance closed by two of the thermostatic ele'ctrode s, and the open circuit arranged for closure by the third thermostatic electrodes.

JOE L WALES WHITE:

Witnesses:

H. W. TIMBALL,

'Gno. B SMITH. 

